Nonword repetition as a behavioural marker for inherited language impairment: Evidence from a twin study

The Children's Nonword Repetition Test (CNRep) was given to 39 children with persistent language impairment (LI), 13 with a history of having received speech-language therapy (resolved LI), and 79 controls, all aged from 7 to 9 years. The children with LI were twins who had participated in a previous genetic study. Children with resolved LI, as well as those with persistent LI, were significantly impaired on the CNRep. Comparisons of MZ and DZ twins indicated significant heritability of a CNRep deficit. It is concluded that CNRep provides a marker of the phenotype of heritable forms of developmental language impairment. Copyright (C) 1996 Association for Child Psychology and Psychiatry.